The overall goal of this project is to develop better screening methods to provide castration-resistant prostate cancer patients with more appropriate chemotherapeutic agents. The focus of Objective 1 is the development and validation of a CYP1 81 *3 genotype assay using a PCR based Taqman allelic discrimination technique suitable for eventual use in a GLP/CLIA-certified environment. The assay will determine the patient's CYP1 81 genotype from a blood sample and will provide a rapid prognostic tool to predict survival rate and propensity to respond to Docetaxel or similar agents. Studies outlined in Objective 2 will examine mechanisms of CYP1 81-mediated effects on Docetaxel chemotherapy, emphasizing the interaction of estrogen and its metabolites with Docetaxel. Impacts on cellular health status will be assessed by measuring oxidative stress and by examining apoptosis/necrosis, relative cell survival, influence on cell cycle and micronuclei formation using a multiplex flow cytometry-based assay. Effects on microtubules will be assessed using an assay measuring tubulin polymerization within the cell. Gene expression profiling will be used to assess mechanisms of toxicity known to be driven by mitotic spindle poisons like Docetaxel. The ultimate goal (Phase II) is to establish a cellular-based assay to use as a rapid screen for testing potential candidate drugs.